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eefa864b JK |
1 | config PAGE_EXTENSION |
2 | bool "Extend memmap on extra space for more information on page" | |
3 | ---help--- | |
4 | Extend memmap on extra space for more information on page. This | |
5 | could be used for debugging features that need to insert extra | |
6 | field for every page. This extension enables us to save memory | |
7 | by not allocating this extra memory according to boottime | |
8 | configuration. | |
9 | ||
ee3b4290 AM |
10 | config DEBUG_PAGEALLOC |
11 | bool "Debug page memory allocations" | |
7bc32f6f AM |
12 | depends on DEBUG_KERNEL |
13 | depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC | |
7d46d9e6 | 14 | depends on !KMEMCHECK |
e30825f1 | 15 | select PAGE_EXTENSION |
7bc32f6f | 16 | select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC |
ee3b4290 AM |
17 | ---help--- |
18 | Unmap pages from the kernel linear mapping after free_pages(). | |
ea6eabb0 CB |
19 | Depending on runtime enablement, this results in a small or large |
20 | slowdown, but helps to find certain types of memory corruption. | |
ee3b4290 | 21 | |
7bc32f6f AM |
22 | For architectures which don't enable ARCH_SUPPORTS_DEBUG_PAGEALLOC, |
23 | fill the pages with poison patterns after free_pages() and verify | |
24 | the patterns before alloc_pages(). Additionally, | |
25 | this option cannot be enabled in combination with hibernation as | |
26 | that would result in incorrect warnings of memory corruption after | |
27 | a resume because free pages are not saved to the suspend image. | |
28 | ||
ea6eabb0 CB |
29 | By default this option will have a small overhead, e.g. by not |
30 | allowing the kernel mapping to be backed by large pages on some | |
31 | architectures. Even bigger overhead comes when the debugging is | |
32 | enabled by DEBUG_PAGEALLOC_ENABLE_DEFAULT or the debug_pagealloc | |
33 | command line parameter. | |
34 | ||
35 | config DEBUG_PAGEALLOC_ENABLE_DEFAULT | |
36 | bool "Enable debug page memory allocations by default?" | |
37 | default n | |
38 | depends on DEBUG_PAGEALLOC | |
39 | ---help--- | |
40 | Enable debug page memory allocations by default? This value | |
41 | can be overridden by debug_pagealloc=off|on. | |
42 | ||
6a11f75b | 43 | config PAGE_POISONING |
7bc32f6f | 44 | bool |